Tubular members may be utilized to support headrests, armrests, or other components of a vehicle seat, and such tubes may include notches that are engaged by a device to prevent or otherwise control movement of the headrest or other seat component relative to the other seat components. Various machines and methods have been developed for forming notches in metal bars and tubes used in this and other applications. However, known tooling and processes for forming notches may suffer from various drawbacks.